2-Methylhexane

Chemical Properties

clear colorless liquid

Physical properties

Clear, colorless, flammable, watery liquid with an odor similar to pentane, 2-methylpentane, 3- methylpentane, hexane, and 3-hexane. An odor threshold concentration of 420 ppb_v was reported by Nagata and Takeuchi (1990).

Uses

Organic synthesis.

Uses

2-Methylhexane is mainly used as a model iso-alkane in studies relating to iso-alkane oxidation, vapor-liquid phase equilibria of heptane isomers and catalytic cracking.

Hazard

Flammable, dangerous fire risk, explosivelimits in air 1–6%.

Source

Schauer et al. (1999) reported 2-methylhexane in a diesel-powered medium-duty truck exhaust at an emission rate of 570 μg/km.
Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of 2-methylhexane was 2.6 mg/kg of pine burned. Emission rates of 2-methylhexane were not measured during the combustion of oak and eucalyptus.
California Phase II reformulated gasoline contained 2-methylhexane at a concentration of 15.3 g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 2.88 and 372 mg/km, respectively (Schauer et al., 2002).

Environmental Fate

Biological. Riser-Roberts (1992) reported 2- and 5-methylhexanoic acids as metabolites by the microorganism Pseudomonas aeruginosa.
Photolytic. Based on a reported photooxidation reaction rate constant of 6.80 x 10^-12 cm³/molecule?sec with OH radicals, the half-life of 2-methylhexane is 25 h (Altshuller, 1990).
Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 2- Methylhexane will not hydrolyze because it does not contain a hydrolyzable functional group.

Purification Methods

Purify it by azeotropic distillation with MeOH, then wash it with water (to remove the MeOH), dry it over type 4A molecular sieves and distil it. [Beilstein 1 IV 397.]